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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        const promise1 = new Promise((resolve, reject) => {
            console.log('promise1')
            resolve('resolve') // 立刻 第一个宏任务 pending -> fulfilled

        })
        // promise1.then 还是Promise
        const promise2 = promise1.then(res => {
            console.log(res)
            return new Promise((resolve,reject) => {
                resolve()
                console.log(promise2,'++++++++')
            })
        })
        console.log(promise2, '---')
        console.log(1, promise1)
        console.log(2, promise2)
    </script>
</body>
</html>